Swimming and Campylobacter infections (1).A matched case-control study case-control study, n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. was conducted to study risk factors for domestically acquired sporadic sporadic /spo·rad·ic/ (spo-rad´ic) occurring singly; widely scattered; not epidemic or endemic. spo·rad·ic or spo·rad·i·cal adj. 1. Occurring at irregular intervals. 2. Campylobacter Campylobacter Genus of gram-negative spiral-shaped bacteria infecting mammals. Many species, especially C. fetus, cause miscarriage in sheep and cattle. C. jejuni is a common cause of food poisoning. Sources include meats (particularly chicken) and unpasteurized milk. infections in Finland. Swimming in natural sources of water was a novel risk factor. Eating undercooked meat and drinking dug-well water were also independent risk factors for Campylobacter infection. ********** Campylobacter jejuni Campylobacter jejuni Vibrio jejuni, Campylobacter fetus ssp jejuni A curved or spiral gram-negative bacillus with a single polar flagellum Epidemiology Linked to contact with domestic and farm animals, unpasteurized milk, primates, day care and C. cob are leading causes of human bacterial gastroenteritis
Bacterial gastroenteritis is an inflammation of the stomach and intestines caused by bacteria or bacterial toxins. in industrialized in·dus·tri·al·ize v. in·dus·tri·al·ized, in·dus·tri·al·iz·ing, in·dus·tri·al·iz·es v.tr. 1. To develop industry in (a country or society, for example). 2. countries (1,2). In 1998, in Finland, the number of reported Campylobacter cases exceeded that of salmonella salmonella Any of the rod-shaped, gram-negative, non-oxygen-requiring bacteria that make up the genus Salmonella. Their main habitat is the intestinal tract of humans and other animals. for the first time (2). A similar increase in Campylobacter incidence is evident in other industrialized countries (1,3), but the reason for this finding remains unknown (1). Most human Campylobacter infections are sporadic, and a seasonal peak in the distribution of the infections occurs during the summer months in several countries, including Finland (1-4). A variety of risk factors for Campylobacter infections have been identified, including handling and eating poultry (1,3,5-7) and drinking unpasteurized Adj. 1. unpasteurized - not having undergone pasteurization unpasteurised milk (1,3,5,7) or untreated water (1,8,9). In Finland, several waterborne outbreaks have been reported (10), but risks associated with sporadic Campylobacter infections are largely unknown (Table 1). In our case-control study, we identified risk factors for and possible sources of infection for domestically acquired sporadic Campylobacter infections in Finnish patients from three geographic areas during the seasonal peak from July 1 to September 30, 2002. The Study Three clinical microbiology Clinical microbiology The adaptation of microbiological techniques to the study of the etiological agents of infectious disease. Clinical microbiologists determine the nature of infectious disease and test the ability of various antibiotics to inhibit or kill laboratories that served patients in the southern, central, and eastern parts of Finland participated in this multicenter, matched case-control study. A case-patient was defined as a person with stool culture Stool Culture Definition Stool culture is a test to identify bacteria in patients with a suspected infection of the digestive tract. A sample of the patient's feces is placed in a special medium where bacteria is then grown. , collected during the study period and tested at one of the three laboratories, that was positive for C. jejuni or C. coil Patients from both outpatient clinics and hospitals were included. When a Campylobacter-positive patient was identified, personnel from the microbiology microbiology: see biology. microbiology Scientific study of microorganisms, a diverse group of simple life-forms including protozoans, algae, molds, bacteria, and viruses. laboratory contacted the clinic or hospital for more information on the patient's recent travel history. If the patient had not traveled abroad within 2 weeks before illness, that patient's physician was contacted by phone and was asked to send to the patient information about our study and a questionnaire and a prepaid pre·pay tr.v. pre·paid, pre·pay·ing, pre·pays To pay or pay for beforehand. pre·pay  ment n. envelope to be returned to the researchers.Two age-, sex-, and municipality-matched controls were chosen for each case-patient. Controls were selected from the Population Register Center, Espoo, Finland, an official register of all Finnish residents. Potential controls were contacted by mail and asked to fill in a questionnaire and mail it back in a prepaid envelope. Exclusion criteria exclusion criteria AIDS Donor exclusion criteria, see there for the controls were Campylobacter infection, at least three loose stools per day, abdominal pain Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem. , or fever 30 days before filling out the questionnaire. If the questionnaire was not returned within 2 weeks, a new pair of controls was chosen, leading to a maximum of four controls per case. The questionnaire sent to patients included questions on the disease, travel in and outside of Finland, dietary intake of food items (meat, fish, vegetables, fruit, and dairy products dairy products dairy npl → produits laitier dairy products dairy npl → Milchprodukte pl, Molkereiprodukte pl ), quality of drinking water drinking water supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. , contact with pets and other domestic animals, and swimming in water from natural sources. The controls answered similar questions except for those concerning illness. Case-patients and controls were excluded if they had traveled abroad within 2 weeks before illness (case-patients) or filling in the questionnaire (controls). The study was approved by the Ethics Committee ethics committee A multidisciplinary hospital body composed of a broad spectrum of personnel–eg, physicians, nurses, social workers, priests, and others, which addresses the moral and ethical issues within the hospital. See DNR, Institutional review board. of the Hospital District of Helsinki and Uusimaa. For sample-size calculation, the case-control ratio was 1:2. The exposure level among patients and controls was assumed to be 30% and 15%, respectively. The study was based on the estimate that 97 patients would be needed for the 5% significance level with 80% power. Only patients with at least one matched control matched study, matched control a comparison between groups in which each subject animal is matched by a comparable animal in terms of age and all other measurable parameters. Called also matched or paired control. were accepted for the final study set. Data entry was performed by EpiData 2.1b (EpiData Association, Odense, Denmark), and statistical analyses were made with EpiInfo 2002 (Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. , Atlanta, GA). For risk factors with 95% confidence interval confidence interval, n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. (CI) above one, conditional logistic regression In statistics, logistic regression is a regression model for binomially distributed response/dependent variables. It is useful for modeling the probability of an event occurring as a function of other factors. examined these independently related to Campylobacter infection. Of the 316 patients with stool culture-verified Campylobacter during the study period, 208 had no known foreign travel; the 634 controls also had not traveled outside of Finland. A total of 151 (73%) patients and 309 (49%) controls returned the questionnaire. Of the patients, 11 were excluded because of traveling abroad (according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. the questionnaire), 3 for misunderstanding or missing information, 5 for having too long a delay (>37 days) between onset of symptoms and answering the questionnaire, and 11 because the delay between symptoms and answering the questionnaire could not be defined. In addition, a matched control was unavailable for 21 patients. Of the controls, 172 were excluded for the following reasons: traveling abroad (17 controls), gastrointestinal symptoms (56 controls), missing information (21 controls), and previous Campylobacter infection (2 controls); 76 were omitted because of the lack of a matching case. The final analysis was made up of 100 patients and 137 controls. A total of 99 patients were infected in·fect tr.v. in·fect·ed, in·fect·ing, in·fects 1. To contaminate with a pathogenic microorganism or agent. 2. To communicate a pathogen or disease to. 3. To invade and produce infection in. with C. jejuni and 1 with C. coli. All cases were sporadic and not associated with any known outbreaks. Regional distribution and demographic characteristics of patients and controls are presented in Table 2. Patients and controls were matched in doubles (66 patients), triples (31 patients), and quadruples (3 patients). Patients filled in the questionnaires within 3 to 37 days from onset of illness, with a median delay of 16 days. The median interval between onset of illness of the patients and their controls responding to the questionnaire was 32 days. The median delay between patients and controls filling in the questionnaire was 15 days. The total number of exposures analyzed was 82. Factors significantly associated with an increased or a reduced risk for Campylobacter infection are shown in Table 3. Of the 14 patients who ate undercooked or raw meat, 57% had eaten poultry and 36% minced meat Minced meat may refer to:
Of the four significant risk factors in the initial univariate analysis, three were independently associated with Campylobacter infection in multivariate analysis multivariate analysis, n a statistical approach used to evaluate multiple variables. multivariate analysis, n a set of techniques used when variation in several variables has to be studied simultaneously. : tasting or eating undercooked or raw meat, drinking untreated dug well water, and swimming in natural sources of water (Table 1). At least one of these three epidemiologically associated risk factors was found in 67% of the patients. Conclusions We identified, to our knowledge for the first time, swimming in natural sources of water to be an independently associated risk factor for sporadic Campylobacter infection. As the infective infective /in·fec·tive/ (in-fek´tiv) 1. capable of producing infection. 2. infectious (1). in·fec·tive adj. Capable of producing infection; infectious. dose for Campylobacter infection is likely low, contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. surface water may cause infection through swimming; campylobacters are commonly found in natural waters, such as rivers, streams, and lakes (12). However, in contrast to our study, in a recent Norwegian study (9), swimming in the sea, lakes, and swimming pools was associated with a reduced risk for Campylobacter infection. Our study showed that private water supplies present a significant risk factor for sporadic Campylobacter infection. Kapperud et al. (9) also found that exposure to surface water or drinking nondisinfected water caused an increased risk. In Finland, in addition to the 310,000 households that use private wells, approximately 300,000 summer cottages have private water supplies (13). Dug wells are susceptible to surface water contamination. Furthermore, the summer of 2002 was exceptionally dry in Finland, resulting in poor water quality in these wells because of low groundwater levels. In our study, drinking water from a large water plant protected against sporadic Campylobacter infection. Large water plants usually have surface water as their source and use multistage mul·ti·stage adj. 1. Functioning in more than one stage: a multistage design project. 2. Relating to or composed of two or more propulsion units. purification purification, in religion, the ceremonial removal of what the religion deems unclean. The usual agents of purification are water (as in baptism), bodily alteration (as in circumcision), and fire. and disinfection disinfection, n the process of destroying pathogenic organisms or rendering them inert. disinfection, full oral cavity, n a procedure used to reduce active periodontal disease, usually completed within a certain short time frame. procedures before drinking water is distributed to consumers, which substantially reduces risk for waterborne infections. Eating strawberries, although a significant risk factor in univariate analysis, was not an independent risk factor in the multivariate analysis. During the same time period but outside the study region, a small cluster of cases was reported for which the suspected source was eating strawberries directly from the field (14). Reduced risk for the disease was associated with eating other berries, such as red and black currants and blueberries, and carrots. These findings are consistent with the literature (7-9), although no one fully understands the role of these protective factors. In Finland, because most sporadic Campylobacter infections occur during July to September, our study could not identify risk factors that may have varied seasonally. The median age of our patients and controls was considerably high (51 years of age), which may have influenced the results. This age group, however, may be typical for Finland, since in our previous study sporadic, domestically acquired Campylobacter infections were frequent in certain parts of the country in elderly men (15). In addition to the known risk factor of eating raw or undercooked meat, this study clearly identified water as an important risk for domestically acquired Campylobacter infections in the summertime in Finland. The novel finding that swimming in water from natural sources was associated with increased risk for infection further emphasizes the importance of other water-related exposure factors.
Table 1. Matched multivariate analysis of significant risk factors
for domestically acquired sporadic Campylobacter infection,
July-September 2002, Finland (a)
Risk factor Adjusted OR 95% CI 2-tailed p
Tasting or eating raw or 10.79 1.31-89.09 0.0272
undercooked meat
Drinking water from a dug well 3.36 1.37-8.24 0.0082
Swimming in water from natural 2.80 1.23-6.39 0.0145
sources
(a) OR, odds ratio; CI, confidence interval.
Table 2. Patient characteristics
Patients, Controls,
Characteristic N = 100 (%) N = 137 (%)
Sex
Male 42 (42) 56 (41)
Female 58 (58) 81 (59)
Age (y)
1-4 4 (4) 6 (4)
5-9 1 (1) 2 (2)
10-19 3 (3) 5 (4)
20-29 13 (13) 18 (13)
30-39 9 (9) 13 (10)
40-49 15 (15) 18 (13)
50-59 26 (26) 32 (10)
[greater than or equal to] 60 29 (29) 43 (31)
Median age (y) 51 51
Municipality
Helsinki 35 (35) 47 (34)
Kuopio 44 (44) 62 (45)
Joensuu 21 (21) 28 (20)
Table 3. Matched univariate analysis of exposure factors for
domestically acquired sporadic Campylobacter infection,
July-September 2002, Finland (a)
Patients, Controls, Adjusted
Risk factor n = 100 n = 137 OR
Increased risk
Tasting or eating undercooked or 14/88 3/124 12.00
raw meat (b)
Drinking water from a dug well 31/96 22/137 3.19
Swimming in water from natural 48/100 40/134 2.27
sources
Eating strawberries 70/89 79/124 2.90
Reduced risk
Eating
Black and red currants 17/73 73/126 0.17
Blueberries 20/73 56/118 0.43
Carrots 43/83 89/126 0.44
Yogurt 51/90 83/121 0.35
Pasteurized milk 55/93 99/131 0.44
Cooked or fried fish 50/93 98/128 0.35
Liver (beef) 4/69 15/105 0.18
Drinking water produced by a large 52/97 88/137 0.52
water plant
Eating at a friend's house 24/49 44/71 0.35
Others
Eating
Minced meat (pork) 45/83 70/116 0.54
Minced meat (beef) 64/90 97/128 0.78
Drinking
Water produced by a small water 23/97 34/137 0.80
plant
Water from bedrock well 20/97 17/137 1.96
Bottled water 15/97 27/137 0.75
Contact with cat 27/88 40/118 0.87
Contact with dog 53/93 76/128 1.02
Contact with farm animals 4/83 9/118 0.36
Eating outside the home 69/98 100/137 0.78
Eating chicken prepared from
Nonmarinated pieces 9/71 20/111 0.32
Marinated pieces 34/81 47/111 0.76
Nonmarinated strips 11/70 13/114 1.06
Marinated strips 19/77 40/118 0.61
Drinking unpasteurized milk 7/80 9/111 1.40
Risk factor 95% CI 2-tailed p
Increased risk
Tasting or eating undercooked or 1.54-93.77 0.0052 (c)
raw meat (b)
Drinking water from a dug well 1.58-6.45 0.0017
Swimming in water from natural 1.24-4.16 0.0089
sources
Eating strawberries 1.21-6.95 0.0287
Reduced risk
Eating
Black and red currants 0.07-0.41 <0.0001
Blueberries 0.21-0.89 0.0115
Carrots 0.24-0.82 0.0039
Yogurt 0.15-0.85 0.0332
Pasteurized milk 0.22-0.85 0.0075
Cooked or fried fish 0.18-0.67 0.0004
Liver (beef) 0.04-0.87 0.0083
Drinking water produced by a large 0.26-1.02 0.0371
water plant
Eating at a friend's house 0.13-0.96 0.0195
Others
Eating
Minced meat (pork) 0.28-1.06 0.0438
Minced meat (beef) 0.42-1.46 0.3459
Drinking
Water produced by a small water 0.37-1.72 0.4528
plant
Water from bedrock well 0.89-4.34 0.1210
Bottled water 0.37-1.51 0.3062
Contact with cat 0.43-1.76 0.5768
Contact with dog 0.55-1.89 0.9385
Contact with farm animals 0.06-2.14 0.1426
Eating outside the home 0.41-1.48 0.3686
Eating chicken prepared from
Nonmarinated pieces 0.10-1.06 0.0274
Marinated pieces 0.38-1.58 0.3613
Nonmarinated strips 0.33-3.46 0.8357
Marinated strips 0.29-1.28 0.1324
Drinking unpasteurized milk 0.45-4.37 0.7768
(a) OR, odds ratio; CI, confidence interval.
(b) Of 14 exposed patients, 13 specified meat type: 8 (57%) had
tasted undercooked poultry, and 5 (36%) had tasted minced meat.
(c) Fisher exact test.
Acknowledgments We thank Heikki Korpela for his comments on the manuscript. The study was partially supported by grants from Finska Lakaresallskapet, Helsinki University's Research Funds, and Helsinki University Central Hospital Helsinki University Central Hospital (HUCH) (in Finnish, Helsingin yliopistollinen keskussairaala (Hyks), in Swedish, Helsingfors universitets centralsjukhus (HUCS)) is the largest university hospital in Finland. Research Funds. (1) This study was in part presented at the 12th International Workshop on Campylobacter, Helicobacter and Related Organisms, Aarhus, Denmark, September 6-10, 2003. References (1.) Friedman J, Neimann J, Wegener HC, Tauxe RV. Epidemiology epidemiology, field of medicine concerned with the study of epidemics, outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause of Campylobacter jejuni infections in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. and other industrialized nations. In: Nachamkin I, Blaser MJ, editors. Campylobacter. 2nd ed. Washington: American Society for Microbiology The American Society for Microbiology (ASM) is a scientific organization, based in the United States although with over 43,000 members throughout the world. It is the largest single life science professional organization and its members include those whose interests encompass basic ; 2000. p. 121-38. (2.) Rautelin H, Hanninen M-L M-L Main Lobe . Campylobacters: the most common bacterial enteropathogens in the Nordic countries. Ann Med. 2000;32:440-5. (3.) Altekruse SF, Stern NJ, Fields PI, Swerdlow DL. Campylobacter jejuni--an emerging foodborne pathogen foodborne pathogen Public health A pathogen–especially bacteria, for which the 'vector' is itself a food. See Airline food. . Emerg Infect infect /in·fect/ (in-fekt´) 1. to invade and produce infection in. 2. to transmit a pathogen or disease to. in·fect v. 1. Dis. 1999;5:28-35. (4.) Nylen G, Dunstan F, Palmer SR, Andersson Y, Bager F, Cowden J, et al. The seasonal distribution of Campylobacter infection in nine European countries and New Zealand New Zealand (zē`lənd), island country (2005 est. pop. 4,035,000), 104,454 sq mi (270,534 sq km), in the S Pacific Ocean, over 1,000 mi (1,600 km) SE of Australia. The capital is Wellington; the largest city and leading port is Auckland. . Epidemiol Infect. 2002;128:383-90. (5.) Studahl A, Andersson Y. Risk factors for indigenous Campylobacter infection: a Swedish case-control study. Epidemiol Infect. 2000:125:269-75. (6.) Kapperud G, Skjerve E, Bean NH, Ostroff SM, Lassen J. Risk factors for sporadic Campylobacter infections: results of a case-control study in southeastern Norway. J Clin Microbiol. 1992;30:3117-21. (7.) Neimann J, Engberg J, Molbak K, Wegener HC. A case-control study of risk factors for sporadic Campylobacter infections in Denmark. Epidemiol Infect. 2003;130:353-66. (8.) Eberhart-Phillips J, Walker N, Garren N, Bell D, Sinclair D. Rainger W, et al. Campylobacteriosis in New Zealand: results of a case-control study. J Epidemiol Community Health. 1997;51:686-91. (9.) Kapperud G, Espeland G, Wahl E, Walde A, Herikstad H, Gustavsen S, et al. Factors associated with increased and decreased risk of Campylobacter infection: a prospective case-control study in Norway. Am J Epidemiol. 2003;158:234-42. (10.) Hanninen M-L. Haajanen H, Pummi T. Wermundsen K, Katila M-L, Sarkkinen H, et al. Detection and typing of Campylobacter jejuni and Campylobacter coli and analysis of indicator organisms in three waterborne outbreaks in Finland, Appl Environ Microbiol. 2003:67:1581-6. (11.) Evans MR, Lane W, Frost JA, Nylen G. A Campylobacter outbreak associated with stir-fried food. Epidemiol Infect. 1998;121:275-9. (12.) Jones K. Campylobacters in water, sewage and the environment. J Appl Microbiol. 2001;90:68S-79S. (13) Korkka-Niemi K. Cumulative geological, regional and site specific factors affecting groundwater quality in domestic wells in Finland. Monographs of the Boreal bo·re·al adj. 1. Of or relating to the north; northern. 2. Of or concerning the north wind. 3. Boreal Environmental Research. The Finnish Environment Institute The Finnish Environment Institute (SYKE) (Finnish: Suomen ympäristökeskus, Swedish: Finlands miljöcentral : 2001. (14.) Hatakka M, Johansson T, Kuusi M, Maijala R, Pakkala P, Siitonen A. Foodborne and waterborne outbreaks in Finland in 2002. Helsinki, Finland: National Food Agency; 2003. (15.) Vierikko A. Hanninen M-L, Siitonen A, Ruutu P, Rautelin H. Distribution of domestically acquired Campylobocter infections in Finland during a seasonal peak. Emerg Infect Dis. 2004;10:127-30. Dr. Schonberg-Norio works in the Department of Bacteriology bacteriology Study of bacteria. Modern understanding of bacterial forms dates from Ferdinand Cohn's classifications. Other researchers, such as Louis Pasteur, established the connection between bacteria and fermentation and disease. and Immunology immunology, branch of medicine that studies the response of organisms to foreign substances, e.g., viruses, bacteria, and bacterial toxins (see immunity). Immunologists study the tissues and organs of the immune system (bone marrow, spleen, tonsils, thymus, lymphatic at Haartman Institute, University of Helsinki The University of Helsinki is not to be confused with the Helsinki University of Technology. The University of Helsinki (Finnish: Helsingin yliopisto, Swedish: Helsingfors universitet . Her research focuses on Campylobacter infections. Address for correspondence: Hilpi Rautelin, Department of Bacteriology and Immunology, Haartman Institute, P.O. Box 21, FIN-00014 University of Helsinki, Finland: fax: 1358-9-1912-6382; email: hilpi.rautelin@ helsinki.fi Daniela Schonberg-Norio, * ([dagger]) Johanna Takkinen, * Marja-Liisa Hanninen, * Marja-Leena Katila, ([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) Suvi-Sirkku Kaukoranta, ([section]) Leena Mattila, ([dagger]) and Hilpi Rautelin * ([dagger]) * University of Helsinki, Helsinki, Finland; ([dagger]) Helsinki University Central Hospital, Helsinki, Finland; ([double dagger]) Kuopio University Hospital, Kuopio, Finland; and ([section]) North Karelia Central Hospital, Joensuu, Finland |
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